Tractor Repair: Case 1070 Diesel Stuck Throttle, fuel injection pump, throttle linkage

Question
Hi, I have a Case 1070 Diesel tractor and the throttle is stuck at about 80%.  It will increase beyond that but not come back below that position.  The throttle lever in the cab moves freely through most of the full travel but when you hit the 80% point and push beyond that there is some resistance as the engine speed increases. I do a lot of my own mechanical maintenance but this tractor is new to me and I have no experience with it.  I do have a 2 volume set of Case maintenance manuals, but they don't seem to address the throttle linkage assembly.  The fuel control lever on the fuel injection pump (I think it's called) does not move noticeably at different throttle control lever positions. The linkage is connected at the throttle lever and at the fuel injection pump. Where should I look first? I really appreciate experts like you who take your own personal time to help others.  Thanks!

Answer
  Even though the hand throttle lever moves freely, the foot throttle is probably sticking.  The hand throttle cable goes down under the platform and connects to the foot throttle, and the linkage from the foot throttle is what actually operates the arm on the injection pump.  There is a cross shaft and linkage behind the engine under the front of the platform that sometimes needs some penetrating oil to free it up.  Shoot some on the  foot throttle pedal pivot also.